444 



parallel to each other, and about l inch apart. If made to ap- 

 proach each other on one side, by revolution in opposite directions 

 on vertical axes, a piece of paper being between to prevent ice con- 

 tact, the torsion force set up caused them to separate when left to 

 themselves ; but if the paper were away and the ice pieces were 

 brought into contact, by however slight a force, they became one, 

 forming a rigid piece of ice, though the strength was, of course, very 

 small, the point of adhesion and solidification being simply the con- 

 tact of two convex surfaces of small radius. By giving a little 

 motion to the pail, or by moving either piece of ice gently in the 

 water with a slip of wood, it was easy to see that the two pieces were 

 rigidly attached to each other ; and it was also found that, allowing 

 time, there was no more tendency to a changing shape here than in 

 the case quoted above. If now the slip of wood were introduced 

 between the adhering pieces of ice, and applied so as to aid the 

 torsion force of one of the loops, i. e. to increase the separating force, 

 but unequally as respects the two pieces, then the congelation at the 

 point of contact would give way, and the pieces of ice would move 

 in relation to each other. Yet they would not separate ; the piece 

 unrestrained by the stick would not move off by the torsion of its 

 own thread, though, if the stick were withdrawn, it would move 

 back into its first attached position, pulling the second piece with it ; 

 and the two would resume their first associated form, though all the 

 while the torsion of both loops was tending to make the pieces 

 separate. 



If when the wood was applied to change the mutual position of 

 the two pieces of ice, without separating them, it were retained for a 

 second undisturbed, then the two pieces of ice became fixed rigidly 

 to each other in their new position, and maintained it when the 

 wood was removed, but under a state of restraint ; and when suffi- 

 cient force was applied, by a slight tap of the wood on the ice to 

 break up the rigidity, the two pieces of ice would rearrange them- 

 selves under the torsion force of their respective threads, yet remain 

 united ; and, assuming a new position, would, in a second or less, 

 again become rigid, and remain inflexibly conjoined as before. 



By managing the continuous motion of one piece of ice, it could 

 be kept associated with the other by a flexible point of attachment 

 for any length of time, could be placed in various angular positions 



